The present disclosure relates to optics, more specifically to zinc sulfide-containing optical elements.
Zinc sulfide is a durable material that is intrinsically transparent to relatively long electromagnetic wavelengths in the far-infrared (IR) range. Such properties contribute to its use in applications that need IR transmission capability, such as in IR detectors and missile domes.
For some applications, the performance of zinc sulfide optical elements may be improved by coating or treating the zinc sulfide with organic polymers. However, due to the fundamental chemical differences between the ionic salt-like structure of the zinc sulfide and the non-polar nature of the polymers, the organic polymers may poorly adhere to the zinc sulfide surfaces. These differences in the chemical nature of the two materials may result in poor wetting of the zinc sulfide and lead to poor adhesion.
In other systems, adhesion promoters or primers may be used to couple the organic polymers to the inorganic surfaces. For example, in glasses, silanes may be used as such a promoter/primer.